2*acos(x)
-2 ----------- ________ / 2 \/ 1 - x
-2*x ----------- 3/2 / 2\ \1 - x /
/ 2 \ | 3*x | -2*|1 + ------| | 2| \ 1 - x / --------------- 3/2 / 2\ \1 - x /